Scientist have discovered a new strain of the Human Immunodeficiency Virus (HIV) in Cuba, which is twice as aggressive as the regular strain.

Researchers published a report in the medical journal, EbioMedicine this month, explaining that the new strain, which progresses to full-blown Acquired Immune Deficiency Syndrome (AIDS) at a much quicker rate, occurs when a person acquires several strains of the virus from having unprotected sex with multiple HIV-infected partners.

All the strains of the virus acquired from the different partners then combine within that person to produce a recombinant strain of the virus. The report said that those infected with the recombinant virus would transition to AIDS within just three years.

The research team compared the blood of 73 recently-infected patients with the new strain of HIV, 52 of whom had been diagnosed with AIDS, with blood from 22 patients who had progressed to AIDS after the normal “healthy” period of infection with HIV.

In a normal course of HIV infection, the virus attaches itself to proteins on the membranes of cells called co-receptors, before actually penetrating the cell. The first co-receptor that HIV anchors to is known as CCR5. After several years of “normal health”, the virus switches to the CXCR4 protein, which results in a faster progression to AIDS.

The new Cuban strain, HIV makes the transition to CXCR4 more quickly than in the other strains, lessening the amount of healthy years a person has. Scientists compared recently infected patients with the recombinant form of HIV to patients who had progressed to AIDS after the usual period of infection. The comparison showed that those with the new strain had abnormally high doses of the virus, as well as high numbers of defensive molecules called RANTES.

RANTES are the body’s natural response to the presence of the virus. High amounts of the protein means that the virus bypassed this usual defense mechanism and found another way into the cell.
Anne-Mieke Vandamme, study author and medical professor at Belguim’s University of Leuven, told the international media that the findings are conclusive that the patients in the study progressed to AIDS at an accelerated rate, because they all had tested HIV negative just two years earlier.

According to the Center for Disease Control in the United States, HIV/AIDS dates back to as far as 1981 when the first patients began dying from an unknown illness. The World Health Organization (WHO) estimated that by the end of 2013, 35 million people were living with HIV globally, 2.1 million people became newly infected, and1.5 million died of AIDS-related causes.